Ground speed and course indicator



Jail. 19, 1932. BREDQUW 1,842,067

GROUND SPEED AND COURSE INDICATOF Filed Oct. 6, 1928 1 I, INVENTOR.

flame/- A. 5/6400: BY

A TTORNEY Patented Jan; 19, 1932 UNITED STATES PATENT OFFICE Applicationfiled October 8, 1928. Serial No. 810,863.

My invention relates to course finders and more particularly to meansand methods for indicating positions and speeds of an airplane, theprincipal object of the invention being to assist the aviator indetermining the ground speed of his plane.

In air travel, large distances are covered in relatively short periodsand maps large enough for easy reading by the aviator while he isoperating his machine, would be cumbersome and inconvenient to installand use.

A particular object of the invention therefore is to provide the mapdata for an aviators course on a strip, to move the strip synchronouslywith the passage of the aviator over the territory indicated on the map,to indicate the position of the plane in relation to the prescribedcourse, and to adapt an indicator for registry with points on the mapwhereby the aviator may at a glance estimate his position and hisrelation to the course.

One of the troublesome problems in aviation is the estimation of therelation between the rate at which an airplane is passing from one pointto another, and being commonly designated the ground speed; the aviatorhaving means for noting the air speed. An aviator may be moving at anair speed of 150 miles an hour while actually progressing from one pointon the ground to another point at 100 miles an hour, because of a headwind that reduces his ground speed. Conversely, the ground speed may be150 miles an hour while the air speed is 100 miles an hour, when thewind assists progress.

An aviator may have supplied his tank with fuel for a jump of 100 miles,the supply not being sufficient to carry him 100 miles against a headwind. At present determination of the ground speed involves manyobservations and mental computations.

Further objects of the invention therefore are to enable the aviator tokeep an accurate check of ground speed; to provide an indicator ofground speed which may be quickly and easily adjusted upon change of airspeed, and to combine a ground speed indicator with an indicator adaptedto disclose the relation of the actual course of the aviator to aprescribed course.

In accomplishing these and other objects of the invention, I haveprovided improved details of structure, the preferred forms of which areillustrated in the accompanying drawings, wherein:

Fig. 1 is a perspective View of an air travel indicating deviceembodying niy invention, the walls of the housing being broken away todisclose operatin elements.

Fig. 2 is a plan view of the device, tion of the upper wall being brokento disclose interior structure.

Fig. 3 is an enlarged detailed perspective view of a governor brake, thehousin top, governor and governor shaft being s own fragmentarily andpartly in section.

Fig. 4 is an enlarged detail fragmentary View of the outer end of thestrip supporting cylinder and means for attaching the strip to thecylinder.

Referring in detail to the drawings:

1 designates a housing including side walls 2 and having a cover 3provided with a sight opening 4., 5 and 6 designate cylinders rotatablysupported in the housing. 7 designates a strip of flexible material suchas tough paper, which for my present purposes, is provided withlongitudinally distributed indicia such as the signs 8, 9 and 10indicating towns, and constituting the strip a map, the opposite ends ofthe map being secured to the cylinders by suitable means laterdescribed. Rods or rollers 11 parallel with the cylinders are rotatablysupported from the housing adjacent the upper edge thereof and adjacentopposite ends of the housing, and the map passes over the rollers and isthus extended in a relatively long horizontal plane adjacent the sightopening 4. A thumb wheel 12 mounted on the outer end of one of thecylinders, for example the cylinder 6, has a larger diameter than thecylinder and extends through a slot 13 of the cover 3 so that it may befrictionally operated for rotating the cylinder 6 to wind the mapthereon. A resilient belt 14 runs on pulleys 15 and 16 on the outer endsof the two cylinders, whereby rotation of the thumb wheel 12 will causethe two cylinders to rotate synchronously and the map may be a porawayWound in either dire :tion from one cylii'ider to the other selectively.

A bar 1? mounted. in the cover for lined support with reference to thehousing Attends transversely across the sight opening at a convenientposition -ior indicating a line transverse to the tourse of the aviatonnd a clip 18 comprising a pointer slidahle on the bar may be fixed at adesired position thereon by a thumb screW 19.

The map is further provided for my purposes with a line 20 installed onthe map to indicate the predetermined course of the avi ator, between astarting point and a destination, the line not necessarily extendingparallel with the side edges of the strip and us uolly extendingangularly to the side edges of the map.

Ihe map may theretore ne inoved spondingly to the a over the ground andthe indicating cli be shifted to regis with e point on th and assist inquick visuel detection oi? digressions from the course, egrees olt dig1ression, and distances other points on the map.

I further provide for constant in: veinent of the map by means i motorrepresented. Toy the housing; 2]. and. not ed snitehle sour of energy,for exam c 5 i i of the motor ertenoing outw 1 y from too housing 1 andbeing provided with a key 23 whereby the svrinn; may he Wound o i upenergy for inovirng the (i limeri- 3- motor may he geared to the ofwider y ml? to, in -n l.

a gear train such as the pinion 22st on the morotated from the pinion 24e 2? on the cylinder 6 meshed witli the W( in er g1; ing the cylinder 6through :1 star clutch memher 28 so that the cylin i from the thumbWheel I further provide means tor ind'c: v

speed at Which the plane is FROVJIIU:

i p r erence to points on the round, 1 preferably a shalt E sup 'iortedfro cts 30 and 31 fixed to the housing: at

ninioi a worm meshed with a from a bevel gear ill on the sl a 253,Whcrel'iy an the on the the lite 41 movement of the collar 3? ton-aidthe collar )6 t) The brake ineinhe' a late ally extending arm 4-5, and avertical screw 46 engaged in an opening l"? of the covell is providedwith er hears ainst said trul and ton 4:8 to depress the arm on .i sl it 7 shoe laterally for adjusting the position oi: the shoe andcontrolling the expansion of the governor. i L spring 49 having oppositeends secured to the cover and the arm of the oralte tends to lift thearm to cause the brake to pivot and thus assure contact or. the screwwith the brake arm, and assure control by the screw of the position ofthe shoe.

1 further provide a circularly disposed scale 50 on the cover adjacentthe screw open" ins", comprising gradnetions 51 nd identiiliyingnumerals 5E2 representt ground speed in miles per hour. 'a'im ringer 53nds radially the over the see of the or l; J 1 screvx' is "l i Nil 'oe 7erner f the cylinders t0 the unitthe speed and map to e Wound speedspeed cor e indicated T is for attaching th' 7 canprise roos e ends cl.t iders to iiista motor the field.

e Wind notices .i 1pc the when the evietor rises Il'rorn The vie his oioi the o Cttt-Oi he re: l

,Q J. 1.1 0 l i that the loan .10 K: "1W LU come the elm LC re. r Y thei no ,he see cr e l i ate more 3w ingto his act val ground s iSuccessive ad ustments synchroni oi? the mov '1' If 4 pain or the limppri I C luiigllitltililiti J. .L] viii, N l. 7 inc ieentnn i. no may iore1: inple, set the clip it i the con e ed l: orally .l'll titl'lJErenresenting a support, a map movably carried by the support, a motorfor moving the map, anindicafor comprising a bar extending transverselyof the map for defining transverse lines thereon, an indicator slidableon the bar for registry with points on said transverse line, means forcontrolling the speed of the map independently of the speed of saidaircraft, and means including a scale for measurin the speed of movementof the map with re erence to the indicator.

, justable to indicate 2. In a ground speed and course indicatorincluding a frame and a map movable onthe 1 frame, a bar mounted on theframe transversely to the direction of movement of the map, and anindicator movably mounted on the bar.

3. A ground speed and course indicator including a support, a mapmovable on the support and provided with point-identifying symbols and astripe connecting selected symbols, a bar fixed to the support andextending transversely of the direction of movement of the map, and anindicator movable on the bar, 7 4. In a ground speed and courseindicator for aircraft including a frame and a support movable on theframe, amap on the support having longitudinally and laterally spacedpoint-identifying symbols and provided with ing means registerable withmeans including a constantly rotating shaft for moving the map on theframe, a second shaft'havin driven relation with the map moving shaft, agovernor on the second shaft, a brake for controlling the governor,means including a screw threaded in the frame for operating the brake, ascale on the frame having graduations in terms of ground speed of theaircraft, and a finger on the brake operatsaid graduations upon rotationof the screw for indicating ground speed of the aircraft.

In a ground speed indicator for aircraft including a frame, a map, andmeans for-moving the map on the frame, a scale on the frame havinggraduations in terms of ground speed of the aircraft, and meanscontrolling rate of movement of the map includ ing a member havingdriven relation with the map moving means, and means for controllingsaid member having a finger movable over said scale.

In testimony whereof I afiix my signature.

' HOMER L. BREDOUW.

a course-indicating line'arranged in prede termined relation with saidsymbols, and a position'indicator mounted on the frame and movable atriglht angles to the direction of for aircraft or the like includingaframe, a

chart, and means for moving the chart on the frame, means havingpredeterminad relation with the chart for indicating the-course of theaircraft, and means on the frame adpoints on said course indicatingmeans.

6. In a device of the character described including a frame, and aconstantly rotating shaft supported by the frame, a governor mounted onthe frame and having driven relation with the shaft, a scale on theframe, a brake for controlling the governor, and a rotative stem foroperating the brake and having an indicating finger registerable withgraduations of the scale to indicate rate of I movement of-s aid shaft.

7. In a ground speed and course indicator for aircraft including aframe, a map, and I

